1. Field of the Invention
The present invention relates to a mobile terminal, a data communication method, and a data communication program stored in a computer-readable storage medium. More particularly, the present invention relates to a mobile terminal, a data communication method, and a computer program for communicating data with servers.
2. Description of the Related Art
Mobile communications systems are widely used in recent years, not only for personal communication, but also for business activities. The latter case requires remote maintenance capabilities and operation management functions in order to prepare for potential damages caused by the loss of mobile terminals used in business, and to reduce the cost for maintenance and operations of such terminals. For this purpose, mobile terminal devices are supposed to have the capability of sending and receiving data for management purposes, besides being able to exchange data of business applications. The former class of data is referred to herein as “management data,” and the latter class of data is referred to herein as “application data.” Specifically, the management data communication includes uploading of operation logs and receiving push services. This kind of data is exchanged by using polling techniques.
The radio communications technologies have enabled the deployment of cellular communications services, wireless local area networks (LAN), and, in Japan, Personal Handyphone Systems (PHS). Those mobile communication environments are, however, limited in their available communication bandwidths. Frequent exchange of management data would consume the available bandwidth excessively and thus choke the communication channels of application data, resulting in communication delays and errors. Some existing specifications for mobile applications only allow a terminal device to perform a single communication session at a time. Mobile terminals using such applications would be seriously affected by the excessive traffic of management data.
A known method for avoiding the above-described problem is to classify the transmit data with different priorities and schedule their communication sessions accordingly. Specifically, the method employs transmit queues to control the flow of data (see, for example, Japanese Unexamined Patent Application Publication No. 2004-200857).
The above queue-based method, however, requires implementation of a complicated control algorithm and thus increases the size of applications since application data and management data are separately controlled. Also the response of application data communication would be worse than what users expect normally, thus making it difficult for the users to do their jobs quickly. More specifically, the use of transmit queues increases the latency of transmit data, i.e., the time lag from depression of a send button to actual transmission of data. This is because the queue-based communication control process involves the multiple steps of entering transmit data into appropriate queues, comparing the priority of each piece of data with others, and selecting data with a high priority before sending it.